Metallic alloy



Patented Feb. 9, 1926.

UNITED STATES PATENT OFFICE.

ERNEST RAYMOND CROSBY, OF CLEVELAND, OHIO, ASSIGNOR TO ALUMINUM MANU- FACTURERS, INCORPORATED, OF CLEVELAND, 01-110, A CORPORATION OF DELA- WARE.

METALLIC ALLOY.

No Drawing. Application filed July 7,

T 0 all whom it may concern:

Be it known that I, ERNEST RAYMOND CROSBY, a citizen of the United States, and a resident of Cleveland, county of Guyahoga, State of Ohio, have invented certain new and useful Improvements in Metallic Alloys, of which the following is a speci fication.

This invention relates to metallic alloys and has as its chief object the provision of an aluminum alloy which will be highly resistant to the corrosive action of chemical compounds, such as organic acids and salts of such acids.

Altho aluminum and its ordinary, wellknown alloys are attacked and corroded by various substances, especially mineral acids and, to a lesser extent, organic acids, 1 have discovered certain aluminum alloy composi tions which are substantially unaffected by the corrosive action of the stron er, more common organic acids and salts t ereof as compared with the present aluminum alloys. 4

Alloys coming within the scope of my discovery and constituting my invention preferably contain in their simplest form only aluminum, silicon and tin, except of course, the usual small amounts of metals which are present in commercial aluminum as impurities but it is permissible to add to such compositions certain other elements such as manganese, etc., when special properties obtainable from those elements are desired.

The silicon content may vary somewhat but should not be less than about 3% or in excess of about 8%. The particular amount of silicon which has been found to give satisfactory results is about 5%, by weight. The tin content need not exceed about 3% and preferably is maintained at about 2%. My improved alloy composition when cast in sand or other slow cooling molds possesses a dense, relatively close-grained structure having a minimum number of small surface openings or pores into which liquid can penetrate. When the metal is cast in quickchilling molds the castings are even more dense and free from surface openings than the sand castings. When sub ected to the corrosive action of strong organic acids, such for instance as acetic, citric and tartaric 1321. Serial No. 482,936.

acids, articles composed of this improved alloy composition are substantially unaffected thereby.

In practicing my invention various methods of alloying the several metals may be employed but the following method has proven satisfactory. An aluminum alloy rich in silicon can be conveniently made, for example, by stirring metallic silicon into molten aluminum at a temperature of about 7 50 to 800 C. The calculated amount of this rich alloy is then added to a quantity' of molten aluminum and after being thoroly stirred and the whole brought to the desired temperature the calculated amount of tin is added immediately before casting.

Having thus fully described my invention, what I desire to secure by Letters Patent is defined in what is claimed.

1. The metallic alloy containing aluminum in a preponderating amount, silicon from about 3% to about 8% tin and from an appreciable amount upto about 3%.

2. The metallic alloy containing aluminum in a preponderating amount, silicon from about 3% to about 8% and about 2% of tin.

3. A metallic alloy containing aluminum in a preponderating amount, about 5% of silicon and up to about 3% of tin from an appreciable amount.

4. A metallic alloy containing 90% or more of aluminum, between about 3% and 8% of silicon and about 2% of tin.

5. The metallic alloy containing about 92% of aluminum, about 5%. of silicon and about 2% of tin.

6. As a new article of manufacture, a casting consisting predominantly of aluminum and containing silicon and tin, characterized by ossessing a dense close grained structure w en cast in a sand mold and by being substantially unafi'ected by the corrosive action of organic acids, the combined contents of silicon and tin ranging between about live and about eleven percent of the alloy, the tin ranging from about two to about three percent.

In testimony whereof I aflix my signature.

ERNEST RAYMOND CROSBY.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,572,382, granted February 9, 1926, upon the application of Ernest Raymond Crosby, of Cleveland, Ohio, for an improvement in Metallic Alloys, an error appears in the printed specification requiring correction as follows: Page 1, line 74, claim 1, for the words tin and read and tin; andthat the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 23d day of March, A. D. 1926.

[snub] M. J. MOORE,

Acting CowwniSsz'oner of Patents. 

